Electron Capture Dissociation (ECD) is important in proteome analysis, specifically, peptide analysis after translational modification. Hereinafter, which system configuration has been used conventionally for ECD and for ECD with other reactions will be described.
Anal. Chem. 1999, 71, 4431-4436 describes that EDC occurs by injecting low energy ions with 1 eV or less in a strong magnetic field of several teslas or more. Since ions and electrons can be efficiently trapped in a strong magnetic field of 1 Tesla or more by moderately controlling a surrounding DC electric field, it is possible to progress ECD reaction.
In Anal. Chem. 2003, 75(13), 3256-3262 as well as in Anal. Chem. 1999, 71, 4431-4436, ECD is performed by injecting low energy ions of 1 eV or less into a strong magnetic field of 1 Tesla or more. Then, by selecting only ions other than a specific ion, multi-photon dissociation is performed by irradiating a laser beam onto the selected ions having a specific m/Z. Moreover, it is not shown in this embodiment, and it is principally possible to perform collision induced dissociation by introducing gas pulses.
In JP-A No. 235412/2005, a weak magnetic field of a few hundred millitesla or less is superimposed in the axial direction in the RF linear-trap. Ions are trapped in the radial direction by an electric field potential created by RF and in the axial direction by a DC electric field potential created by the end electrodes. Moreover, it is described that the energy deposition onto the electrons from the RF electric field is suppressed by the magnetic field applied to the linear-trap axis.
Proceedings of 53rd ASMS Conference and Allied Topics, WP08-135, 2005, San Antonio, Tex. discloses a study of the principles for performing ECD, isolation, and a CID technique in the RF linear-trap described in JP-A No. 235412/2005. Isolation and CID are predicated on the resonance conditions and boundary conditions in an RF electric field in the radial direction as well as in a typical linear-trap.
U.S. Pat. No. 5,783,824 discloses a method where a DC harmonic potential is created in the axial direction in the RF linear trap and ions having a specific m/Z are resonance-ejected, in order, outside the trap.